| 摘要 |
PURPOSE:To reduce a fault repair time by extracting a color burst signal from each of a progressive wave component and a reflecting wave component and obtaining a phase difference of both signals or of demodulation subcarrier signals generated synchronously with both the signals so as to measure a fault location. CONSTITUTION:A distance L(m) corresponding to a half wavelength from the NTSC system color burst signal frequency is expressed as L=299.79/2/3.5795=41.88(m) with respect to the in-line speed of 299790km/sec and this means that a phase difference between two signals is 180 deg., then the fault location distance Lm is obtained by equation I at an optional phase difference THETA degrees. Thus, the fault location is discriminated by equstion I by obtaining the phase difference THETA of both the color burst signals. Since the location of the fault is indicated accurately, the time required for repair of the fault is reduced. |
